One type of glass washing invention to which the present invention is applicable, disclosed in the above-mentioned Ser. No. 117,155, has a carrier that moves linearly to carry glasses from a loading zone at one end of the machine, through successive cleansing zones, to an unloading zone at the other end of the machine. Another type, disclosed in Ser. No. 136,133, has a rotary carrier whereon glasses are carried orbitally from an access zone at which glasses are loaded onto the carrier and removed from it, through cleansing zones, and back to the access zone. In each of these machines, the carrier transports the glasses slowly through one cleansing zone in which they are subjected to sprays of detergent solution discharged from washing nozzles and then through another cleansing zone in which they are subjected to sprays of germicidal rinsing solution discharged from rinsing nozzles.
A basic problem common to all glass washing machines of the general type here under consideration is to prevent substantial mixing of the germicidal solution discharged in the rinsing zone with the detergent solution discharged in the washing zone, notwithstanding that the two solutions are being sprayed simultaneously in adjacent cleansing zones whenever the machine is in operation. The detergent solution must be of a non-foaming type, since the sprayed detergent solution is collected in a retention tank and pumped back to the washing nozzles by means of a centrifugal-type recirculation pump, and foaming of the solution would obviously impair the recirculation process. However, the most commonly used germicidal solution is one that tends to promote vigorous foaming of the detergent solution if mixed with the latter in any substantial proportion. Fortunately, no substantial foaming occurs if only a small proportion of either solution is mixed with the other.
For substantially confining each type of solution to the cleansing zone in which it is discharged, while nevertheless permitting beverage glasses to pass freely from one to the other of these zones, it has been conventional to suspend a vertically slitted waterproof curtain between the two zones, as disclosed in U.S. Pat. No. 3,878,856. A generally similar curtain is hung between a cleansing zone of the machine and an adjacent access zone in which glasses are loaded into the machine and/or unloaded from it. The material now used for such curtains in most commercial glass washing machines is a very supple slitted sheet of specially compounded polyvinyl chloride embossed with a pattern of diamond-shaped nubs on one of its surfaces and with a textile-weave type of pattern on its opposite surface. The slits in this sheet, which extend through most of its height from its bottom edge, define in it numerous narrow strips that permit passage through it of articles being washed, and its embossed surface patterns tend to prevent these strips from curling so that they cooperate to provide a normally straight-hanging spray barrier.
While otherwise satisfactory, this conventional curtain has an undesirably short service life. It has been found that the textured surfaces of the curtain material are to a substantial extent responsible for its relatively poor durability. When a glass or similar article engages against one of the strips defined by the slits in the curtain, there is friction between the article and the textured surface of the strip. This friction is particularly high when the strip is first engaged by a tall article such as a pitcher, which contacts the strip near its top, leaving a substantial length of strip hanging below the zone of contact whereby the engaged portion of the strip is loaded for rubbing force and is sharply flexed by the article. Because of the high temperature of the detergent solution and the leaching action of both solutions, the curtain material gradually loses its suppleness in the course of service, and its strips then begin to break off near their top ends as a result of repeated frictional and flexing engagements with articles being washed. While the gradual embrittlement of such a curtain cannot be prevented, the present invention is based upon a recognition that its useful life can be substantially prolonged by minimizing friction between it and the articles passing through it and by preventing it from being sharply flexed by the passing articles.
The cleansing effectiveness of a glass washer is directly dependent upon a complete and intensive spraying of each of the cleansing liquids against both the inner and the outer surfaces of every glass. Since glasses rest upside down on the carrier, their interior surfaces are sprayed by upwardly discharging nozzles mounted beneath the carrier, and their exterior surfaces are sprayed by downwardly discharging nozzles mounted at a substantial distance above the carrier.
When upwardly sprayed liquid discharged from the lower nozzles impinges the inner surface of the side wall of a glass, it flows upwardly along that surface towards or to the bottom of the glass, and then again follows the inner side surface of the glass as it streams back down. Similarly, upwardly directed spray that enters the glass but does not impinge its sides strikes the inner bottom surface of the glass, clings to it in flow towards the side surface, and then flows down along the interior of the side wall. The interior surface of every glass is thus subjected to intense washing by upwardly directed spray that enters the circle defined by the rim of the glass.
By contrast, spray discharged from an upper nozzle, insofar as it does not fall through spaces between glasses, merely streams down the exterior surface of glasses and therefore, quantity-for-quantity, provides less effective cleaning action than upwardly discharged spray. The significance of this is that a user's lips normally contact only the exterior surface of a glass, leaving on it germs and possibly lipstick or the like that can be removed only with thorough and intensive flushing. The present invention is based in part upon a recognition that, contrary to what obvious considerations would suggest, a substantial portion of the upwardly directed spray discharged from lower nozzles in a glass washing machine can be applied to cleaning the exterior surfaces of glasses, thus materially supplementing the effects of the spray discharged from the upper nozzles.
As pointed out in the above-mentioned Ser. No. 145623, a glass washing machine cannot operate satisfactorily if its spray nozzles are blocked to any substantial extent. That application discloses means for substantially automatic cleaning and deliming of nozzles while the nozzle assemblies remain in place on the machine. Applicable sanitary standards do not require that the nozzle assemblies of a glass washer be removable if they can be easily cleaned while in place. However, such standards require that all splash contact surfaces be readily cleanable; and since every nozzle assembly tends to block access to some such surface, the nozzle assemblies must in any case be readily removable, that is, removable without the use of tools.
U.S. Pat. No. 3,878,856, which discloses a glass washing machine that has enjoyed commercial success, points out that a nozzle assembly consisting of plural independent tubes fitted with spray nozzles is expensive because of the attendant plumbing, and it might have added that such prior nozzle assemblies were not readily removable. That patent discloses a lower nozzle assembly comprising upper and lower pan-like members clamped together in sealed relationship to one another by means of opposite toggle arms to provide a plenum chamber, with the upper one of these members having a number of upwardly discharging nozzle outlets distributed across its top wall. This arrangement provided for easy removal of the nozzle assembly and access to the nozzles, but it was not suitable for an upper nozzle assembly having downwardly discharging outlets, and this may explain why the patent discloses only lower nozzle assemblies that discharge upwardly directed fan shaped sprays. Thus the problem of providing readily removable nozzle assemblies is complicated when each set of nozzles in a glass washing machine comprises both an upper nozzle assembly and a lower nozzle assembly and all nozzles of both assemblies must be connected with a single source of cleansing liquid.